Chris Evert has claimed players are not stepping up to support Maria Sharapova because the US-based Russian has no friends in the game.

Sharapova does not need to look far for enemies, with Martina Navratilova stating on Wednesday that she did not believe her explanation for failing a drug test.

And Dick Pound warned the World Anti-Doping Agency will intervene if it feels tennis does not give the world No 7 a sufficient ban.

The former world No 1 admitted on Monday that she had tested positive for meldonium – a substance banned since January 1 – at the Australian Open.

Evert told ESPN: “It’s hard to tell (the reaction from players) because Maria Sharapova has always isolated herself from the rest of the tennis world, from the players. She doesn’t have a lot of close friendships on the tour.

Isolation: Evert reckons Sharapova isn't getting much support because she has no friends on the tour (Image: WireImage)

"She’s made that known, she can’t be friends with the players. Her friendships are outside of the tennis world, she’s isolated herself. So it's hard.

“I’m not seeing a lot of support from a lot of the players. I think everyone is being mum about the subject right now.

"Whether its shock or whether they don’t want to become involved or have an opinion about it. It’s sort of surprising that not a lot of players have shown their support for her.”

“She will be arguing mitigating circumstances and so on – that is what lawyers are for. They will come up with a sanction and then WADA will have to decide if they think it is appropriate and if they don’t think it is appropriate, there is an appeal to the Court of Arbitration for Sport.”

The Canadian added: “It is a sport which has been under attack for match-fixing and all sorts of other nefarious activities. It is another body blow, a major body blow.”

Sharapova, who owns a sweet brand called Sugarpova, claimed that she had been prescribed meldonium for 10 years by her family doctor because of a family history of diabetes.

Up to 490 athletes may have been taking meldonium during the 2015 European Games in Baku, research has claimed.

Navratilova said: “Good that Maria Sharapova stepped up and told the truth about having been taking meldonium. I don’t believe the reasons though - eg diabetes?”

“I obviously wish her all the best,” said the men’s No 1. “I feel for her with what is happening. I just hope she gets out of this stronger.”

Tennis has had a reputation for not punishing top players since Andre Agassi escaped sanction for a positive test for crystal meth in 1997.

He later revealed in his autobiography that he had lied that the use of the drug was accidental - and the failed test was covered up by the ATP.

Evert added: “To me it’s a good warning to all the superstars out there that they mean serious business and that the sport is not protecting you if you’re bringing in money for the sport, if you’re bringing in TV ratings, it doesn’t matter who you are.